Color print by multiple color development



- and homologues which may ylene compounds ofcorresponding molecular size,

Patented Dec. 16, 1941 UNITED STATES PATENT OFFICE COLOR-P8551! BY 'cono'a- Karl Schinzel. Rochester.

N. Y and Ludwig Schinzel, Troppau, Silesiagsaid Karl Schinael assignor to Eastman Kodak Company, Bachestel, N. Y., a corporation of New Jersey No Drawing.

ApplicationApril I, 1938, Serial No.

3 Claims.

This invention relates to couplers for the color development process of color photographyand particularly to aryl hydrazide couplers} It has been mentioned in our patent application Serial No. 151,811, filed July- 3, 1937, that not only the insoluble salts of sulfonic or carboxylic acids or of acid methylene compounds can be added to the emulsions, but also those of naphthols, phenols and their higher analogues the alkali or the sodium carbonate'oi the developer, it the alkali salts formed do not diffuse.

Of course, the developer may also be prepared with other inorganic or organic bases of the desired strength according to whether decompoggion or stability of the component salt is deed. I 7 It is not easy to add such completely insoluble salts, because, just as in the introduction of insoluble tree phenols, naphthols and acid meththe danger oi crystallizing out exists, especially when'alcoholic or acetonic solutions are used, re-

gardless of the i'actthat according to experiments of Charriou and Valette, the color sensitivity and general sensitivity is reduced (Phot. Ind. 1934, 1306; 1932, 1150; Zeits. if. wiss. Phot. 34, '2613). It is, therefore, well to add the nondiflusing or slightly diffusing alkali salts of higher molecular coupling components (for example,

' palmitylaceto-p-naphthaiide or palmityl-pyraza olone, or of the condensation product 01' acrylic acid, or polyacrylic acid chloride and any aminoe-naphthol), since these salts are not inclined to crystallize out and donot change. the sensitivity. If necessary, solutions of pure'alcoholic or aqueous lye are used according to Claisen. Alkalies here include not only the salts of potassium and sodium but also those of lithium, ammonium, ethylene diamine, diethylene diamine, azine, piperidine; tri-methylene diamine and other aliphatic or mixed higher amines, among which are especially those, which are able to increase the general'or color sensitivity of the silver halide gelatin emulsion. Also, the higher molecular bases are suited for this purpose, as described in the Swiss Patent 1'76,023,24,2 5; 179,945 and German Patent 622,809. One must, however, calculate that after 'longerstorage under the effect 01! the carbon in the atmosphere in some cases these soluble, but not diffusing or hardly diffusing salts eration oi phenol which harms the sensitivity. This is hardly the case with phenols and naphthols which are substituted in the or p-posladded to the emulsions,

be decomposed by. 10

'piperare decomposed with iibtion or in both by halide or by acid methylene compounds which are chlorinated-in the methylene group. In order to oppose this gradual decomposition, an excess of the bases mentioned is of course, only weaker basesor those which have no harmful effect on the gelatin. Also lithium carbonate, guanidine carbonate, piperidine, piperazine, ethylene diamine andhigher aliphatic diamines are consida favorable eflect on .the sensitivity. Less suitable are the di-, or tri-sodlum phosphate, borax, etc. These additions are'also recommended with higher molecular naphthols, phenols, hydroxy quinolines, acid methylene compounds, etc., 1 which in the free state insoluble, and, therefore, hardly reduce the. sensitivity when they are added to the emulsion; they also resist the developers containing sodium carbonate, as the dibenzoyl methane mentioned by Fischer (Phot. Korr. 1914, 21) or the higher 'aceto-acetic arylides.-

Of course, insoluble salts of the naphthois, etc., withsuch organic bases may be added to the emulsions, which are decomposed by stronger organic or inorganic bases in the developer under liberation of the not entirely insoluble, but in itself or in the iorm of the salts of non-diffusing or slightly diilusing naphthol or phenol derivatives, of higher molecular methylene compounds, etc. (German Patents 229,814; 485,523; 514,421; 519,051; U. 8. Pat. 1,953,309).

The hydrazides oi the aceto-acetic homologues.

and analogues, of the a-naphthol-carboxylic acids, hydroxy-quinoline-carboxylic acids, arylalkyl-pyrazolone carboxylic acids and sulfonicacids obtained with asymmetrical diphenyl hydrazine are .especially dimcultly soluble. They may be easily obtained by heating with the ketonic acid ester to above C. or conversion with the other acyl chlorides at ordinary or mod: erately high temperature in the presence of tertiary bases. Their salts with the bases mentioned are usually insoluble, non-diffusing or slightly diflusing through the gelatin emulsions. The residual hydrogen atom of the amino group may also be substituted bymethyl orstill higher alkyls as stearyl, palmityl, ceryl, etc., or the alkylated asymmetrical diphenylhydrazine may be used at once for the hydrazide formation. 0n the other hand, one may also use asymmetrical naphthylphenyl hydrazine, asymmetrical dinaphthyl hydrazine, asymmetrical phenyi-palmityl hydrazine asv well as other arylalphyl' hyused are the. symmetrical substiered for this purpose, especially those which have are almost or entirely tuted aliphatic, aromatic and mixed hydrazines on account of their diflicult preparation. Still better are the bis-hydrazides which are easily obtained from the dihydrazines of benzidine, diphenylene, naphthidine, etc., alkylated or arylated in the amino group. The urea chloride or isocyanate (B. 36,3155) formed from asymmetrical diphenyl hydrazine with phosgene may be converted with amino-a-naphthalene and other coupling components containing an amino group.

We claim:

1. The method of forming a colored image in a photographic layer which comprises developing a silver halide layer in an aromatic amino developer and coupling the oxidation product of the developer with an aryl hydrazide coupler having the structure RAM r a photographic layer which comprises developing a silver halide layer in an aromatic amino developer and coupling the oxidization product of the developer with an aryl hydrazide of a-naphthol carboxylic acid.

' KARL SCHINZEL.

LUDWIG SCHINZEL. 

